1. Technical Field
This invention relates to processes for preparing 1H-imidazo[4,5-c]quinolin-4-amines and to intermediates for use in preparing 1H-imidazo[4,5-c]quinolin-4-amines.
2. Description of the Related Art
Certain antiviral immunomodulator 1H-imidazo[4,5-c]quinolin-4-amines and methods for their preparation are known and disclosed. For example U.S. Pat. Nos. 4,689,338 and 4,929,624 (Gerster) disclose a method involving the step of heating the corresponding 4-chloro compound in the presence of ammonium hydroxide or ammonia under pressure to provide the 4-amino compound. U.S. Pat. No. 4,988,815 (Andre) discloses a process involving amination of the 4-position of a 3-nitro-1,4-dichloroquinoline. This process too involves as a final step the reaction of ammonia with a 4-chloro-1H-imidazo[4,5-c]quinoline.
Milder methods have been used in order to introduce the 4-amino group of 1H-imidazo[4,5-c]quinolin-4-amines. U.S. Pat. No. 5,175,296 (Gerster) discloses a process involving the reaction of a 1H-imidazo[4,5-c]quinoline 5N-oxide with an organic isocyanate and hydrolyzing the product to provide the 4-amino compound. U.S. Pat. No. 5,367,076 (Gerster) discloses a process involving the reaction of a 1H-imidazo[4,5-c]quinoline 5N-oxide with an acylating agent and reacting the product with an aminating agent to provide the 4-amino compound. U.S. Pat. No. 5,395,937 (Nikolaides) discloses a process involving amination of the 4-position of a 3-nitroquinoline-2,4-disulfonate with a substituted amine. The final step of the process involves hydrogenolysis to provide the 4-amino compound.